What's my activity level? How do i find my activity level for TDEE calculator?

Why not use a TDEE calculator which doesn't require "how active am i" question?

Your BMR (Basal Metabolic Rate) is the amount of energy your body burns just to stay alive at rest. Your TDEE (Total Daily Energy Expenditure) includes your BMR plus all the calories you burn from daily life and exercise. While most online calculators give you an estimate, the only way to find your true TDEE is by tracking your food intake against your weight changes over a few weeks. For a deeper dive, see this accurate TDEE calculator.

In step 1 (tdee estimate), it collects your body stats and tries to estimate TDEE as close as possible.

After step 2 (actual/true tdee), your TDEE will be dead on center, not adjustment needed

TDEE is the maintenance calories, if you eat at maintenance your weight will not change if you average it over 3 weeks which should take out water weight fluctuations.

If you eat more than maintenance, you gain weight

if you eat less than maintenance, you lose weight.

Weight gain or lost will be some part fat, some muscle, depending on training/diet